Depositional Environments

Active Tectonic Setting

Any active plate boundary/place ground is rising/sinking

Passive Margin Tectonic Setting

Coastline without plate boundary

Stable Tectonic Setting

A place where basically nothing is happening

Subsidence

When the ground is sinking due to something other than tectonic activity

Tectonic setting influences

Thickness of sediment, and grain texture and composition

Craton

The oldest and most stable part of a continent

Shield

The igneous and metamorphic rocks of a craton

Platform

The sedimentary layer on top of shield

Coastal plains

Places where stuff is washing off mountain ranges

Types of Depositional Environments:

Marine, Transitional, Terrestrial

Types of Transitional Depositional Environments

River Deltas, Coastal Wetlands, Tidal Flats, Estuaries, Lagoons, Beaches, Barrier Island Systems,

Coastal Evolution:

Relative sea level changes resulting from the interaction of global sea level, sediment supply, and tectonic activity

Retrogradational (Transgressive) Coastline

Ocean is moving into land, transitional areas moving inwards

Progradational (Regressive) Coastline

Transitional areas moving seawards

Retrogradational Coastlines have a _________ sequence

Fining-up

Progradational Coastlines have a __________ sequence

Coarsening-up

Aggradational Coastline

Coastline is not moving in or out, but is getting bigger or taller.

Types of Transitional (coastal) Depositional Environments

River deltas, coastal wetlands, tidal flats, estuaries, lagoons, beaches, barrier island systems

Delta plain is made of

sand

Delta front is made of

silt

Prodelta is made of

clay

Coastal wetlands (salt marshes, mangroves) are characterized by

Being intertidal to above high tide, having a lot of vegetation

Tidal Flats

Unvegetated intertidal zones which have a large difference between high and low tide

High-energy environments:

Moving water

Low-energy environments:

Still water

Coarse-grains are associated with __________ environments

high-energy, because they are harder to move

Fine-grains are associated with _________ environments

low-energy, because there is insufficient energy to bring larger clasts to environment

High tectonic activity will have sand grains composed of

feldspar

Low tectonic activity will have sand grains composed of

quartz

Terrestrial Depositional Environments

Fluvial/Alluvial, Alluvial fans/bajadas, playas, lacrustrine (lake), aeolian (wind-blown)

Marine depositional environments

Continental margins, continental shelf, deep ocean basins